IS there a better way to open the most exciting arts festival in the world than by having a world-class orchestra put on a free concert in a football stadium under the directorship of surely the most exciting conductor in the world? I certainly can’t think of one.

Since taking over as director of Edinburgh International Festival (EIF) in 2015, Fergus Linehan has made accessibility one of the watchwords of his tenure, each year putting on a large, free, open-air event to herald the month-long extravaganza’s arrival.

Right from the start, when a crowd of 20,000 watched animations dance across the outside of the Usher Hall in time to choral piece Harmonium, his commissions have been stunning; this year’s opener was no exception.

Straight from a series of concerts at the Hollywood Bowl, superstar conductor Gustavo Dudamel and his Los Angeles Philharmonic took to the stage in Tynecastle Park on Friday night, filling the air with classic movie soundtracks rather than the usual football chants.

From the LA glitz to the Tynecastle hotdogs, the mixture of the high-brow with the low was both inspired and inspiring. It is exactly the kind of levelling that the EIF and the many other arts and cultural festivals that enrich and enliven the city of Edinburgh during the month of August should - and do - aim to achieve.

That could all be under threat, though, with reports at the weekend revealing that the global artists who help make Edinburgh International Festival such a success are no longer willing to accept payment in pounds, demanding that their fees are paid in dollars or euros instead.

Who can blame them? The pound has had a turbulent time since the UK voted to leave the European Union in 2016, with its value falling from $1.50 immediately prior to the referendum to just over $1.20 now. At the same time, while one pound was worth €1.30 in early 2016, its value has fallen to just €1.09 today.

For an event that spends in the region of £13 million putting together a programme that this year is made up of 2,800 artists from 41 countries that creates a serious problem, with the festival’s overall budget falling by 20 per cent in dollar terms since 2016 and by 16% when converted to euros. As Mr Linehan put it in an interview with the Financial Times, the festival’s “buying power is down” thanks to “our currency being in the toilet”.

Though a currency hedge taken out at the start of this year means the festival has not felt the immediate impact Boris Johnson’s premiership has had on the pound, Mr Linehan said that in general terms the Brexit effect is leading to a “paralysis” in long-term planning. “No one wants to say ‘Okay, in five years’ time, this is what are we going to do’ ... because there are so many variables that haven’t really been established yet,” he said.

Nor is the situation likely to get any better. Official statistics released by the Bank of England show that UK businesses are taking pre-emptive action to insulate themselves against further volatility from the pound, with the expectation that Mr Johnson will drag us out of Europe in October without a deal leading to an expectation that the currency will continue to plummet. Indeed, by cutting sterling deposits by £4.1 billion in June at the same time as increasing foreign currency deposits by £4.6bn UK businesses have, according to Janus Henderson economist Simon Ward, taken contingency action “to limit their exposure to a fall in the pound”.

It is a mark of how likely it is that that fall will occur that even the UK Government, in yet another cynical move, has reportedly increased its own net foreign currency reserves by 25% over the past year.

Yet if the pound does fall further, how much more can the EIF do to secure its future buying power? Locking in exchange rates at last year’s levels is one thing, but how much will Mr Linehan and his team be able to do if they lock it in at today’s? What effect will that have on an event that has worked so hard to open itself up to as wide an audience as possible? What would that say about the arts in general?

It is not so long ago that events such as Edinburgh International Festival were seen as out of reach, with enjoyment of its classical repertoire thought of as an elitist sport. But it is no coincidence that this year’s opening EIF concert was held in one of the less-salubrious parts of Edinburgh - in a venue more likely to be associated with pop stars than a world-class orchestra - and featured a programme of music that would be recognisable to everyone. It is a mark of its success that around 70% of the 15,000 people in the audience were thought to have been attending a classical music concert for the first time.

But putting on free concerts that feature world-famous conductors does not come cheap, meaning their future will almost certainly come under threat in a post-no-deal world. Sure there will always be a budget for Edinburgh International Festival, but if that budget has to be spread ever-more thinly when converted to spend on the international stage that can only mean one thing: costs will have to come down and ticket prices will have to rise. It doesn’t take a genius to work out what that would do for inclusivity drives.

Perhaps there are some among us who would rather go back to the days when the arts were the preserve of those in the know and culture was shaped by those who could afford to pay to enjoy it. Perhaps they are the same people who complain each year that Edinburgh’s festivals are getting too big, that the people they attract are a nuisance, and that the boundaries they push should be reined in.

They should be careful what they wish for. It may be an exaggeration to say that Brexit is posing an existential threat to the festivals Edinburgh’s reputation and character have been built on, but the pressures those events are now facing are unprecedented.

That should worry us all. What, after all, would the city be - what would Scotland be - without them?